Active Directory database corrupted

Active Directory database corrupted

Active Directory database corruption is nasty. If you don’t have your image backup or any system state backup. It’s going to cost you time (and money).

We have faced this recently, here are some of the approaches and links to find the solution.

http://www.mombu.com/microsoft/windows-2000-active-directory/t-event-id-474-inconsistent-ntdsdit-151743.html

If you have a recent backup, we recommend you to perform restore operation right away. However if the backup is not recent, and you’ll loose many objects.

You can try to repair the Database, In some situation, certain configurations will be lost with this procedure.

Before you start the computer in Directory Services Restore Mode, obtain the 
password for the offline administrator account.

For more information about how to change the password in Windows Server 
2003, click the following article number to view the article in the Microsoft Knowledge Basehttp://support.microsoft.com/kb/322672/

“Directory Services cannot start” error message when you start your 
Windows-based or SBS-based domain controller
http://support.microsoft.com/?id=258062

Next step:

How to Recover the Database and if it fails try How to Repair the Database 
(Be careful.  Read carefully)

http://support.microsoft.com/default…b;en-us;315131

How to complete a semantic database analysis for the Active Directory 
database by using Ntdsutil.exe
http://support.microsoft.com/default…b;en-us;315136

If you fail to repair a corrupted Active Directory, try the following:
You may try the following steps to recover the corrupted Active Directory.

1. Reboot the server and press F8. Choose Directory Services Restore Mode 
from the Menu.
2. Check the physical location of the Winnt\NTDS\ folder.
3. Check the permissions on the \Winnt\NTDS folder.

The default permissions are:

Administrators – Full Control
System – Full Control

4. Check the Winnt\Sysvol\Sysvol folder to make sure it is shared.
5. Check the permissions on the Winnt\Sysvol\Sysvol share.

The default permissions are:

Share Permissions:
Administrators – Full Control
Authenticated Users – Full Control
Everyone – Read

NTFS Permissions:
Administrators – Full Control
Authenticated Users – Read & Execute, List Folder Contents, Read
Creator Owner – none
Server Operators – Read & Execute, List Folder Contents, Read
System – Full Control

Note: You may not be able to change the permissions on these folders if the 
Active Directory database is unavailable because it is damaged, however it 
is best to know if the permissions are set correctly before you start the 
recovery process, as it may not be the database that is the problem.

6. Make sure there is a folder in the Sysvol share labeled with the correct 
name for their domain.
7. Open a command prompt and run NTDSUTIL to verify the paths for the 
NTDS.dit file. These should match the physical structure from Step 2

To check the file paths type the following commands:

NTDSUTIL
Files
Info

The output should look similar to:

Drive Information:

C:\ NTFS (Fixed Drive) free (2.9 Gb) total (3.9 Gb)
D:\ NTFS (Fixed Drive) free (3.6 Gb) total (3.9 Gb)

DS Path Information:

Database : C:\WINNT\NTDS\ntds.dit – 10.1 Mb
Backup dir: C:\WINNT\NTDS\dsadata.bak
Working dir: C:\WINNT\NTDS
Log dir : C:\WINNT\NTDS – 30.0 Mb total
res2.log – 10.0 Mb
res1.log – 10.0 Mb
edb.log – 10.0 Mb

This information is pulled directly from the registry and mismatched paths 
will cause Active Directory not to start. Type Quit to end the NTDSUTIL 
session.

8. Rename the edb.chk file and try to boot to Normal mode. If that fails, 
proceed with the next steps.

9. Reboot into Directory Services Restore mode again. At the command prompt, 
use the ESENTUTL to check the integrity of the database.
NOTE: You can use NTDSUTIL to check the Integrity, however esentutl is 
usually more reliable.

Type the following command:
ESENTUTL /g “\NTDS.dit” /!10240 /8 /v /x /o
(Note: Type the path without the quotes).

Note: The default path would be C:\Winnt\NTDS\ntds.dit; however it may be 
different in some cases.

The output will tell you if the database is inconsistent and may produce a 
jet_error 1206 stating that the database is corrupt. If the database is 
inconsistent or corrupt it will need to be recovered or repaired . To 
recover the database type the following at the command prompt:

NTDSUTIL
Files
Recover

If this fails with an error, type quit until back at the command prompt and 
repair the database using ESENTUTL by typing the following:

ESENTUTL /p “\NTDS.dit” /!10240 /8 /v /x /o
(Note: Type the path without the quotes).

Note: If you do not put the switches at the end of the command you will 
most likely get a Jet_error 1213 “Page size mismatch” error.

10. Delete the log files in the NTDS directory, but do not delete or move 
the ntds.dit file.
11. The NTDSUTIL tool needs to be run again to check the Integrity of the 
database and to perform a Semantic Database analysis.

To check the integrity, at the command prompt type:

NTDSUTIL
Files
Integrity

The output should tell you that the integrity check completed successfully 
and prompt that you should perform a Semantic Database Analysis.

Type quit.

To perform the Semantic Database Analysis type the following at the NTDSUTIL 
Prompt type:

Semantic Database Analysis
Go

The output will tell you that the Analysis completed successfully.
Type quit and closes the command prompt.

NOTE: If you get errors running the Analysis then type the following at the 
semantic checker prompt:

semantic checker: go fix

This puts the checker in Fixup mode, which should fix whatever errors there 
were.

12. Reboot the server to Normal Mode.

If any of these steps fail to recover the database the only alternative is 
to perform an Authoritative System State restore from backup in Directory 
Services Restore mode.

For more information, please refer to the following articles:

315136 HOW TO: Complete a Semantic Database Analysis for the Active 
Directory
http://support.microsoft.com/?id=315136

265706 DCDiag and NetDiag in Windows 2000 Facilitate Domain Join and DC 
Creation
http://support.microsoft.com/?id=265706

258007 Error Message: Lsass.exe – System Error : Security Accounts Manager
http://support.microsoft.com/?id=258007

265089 Event 1168: Windows 2000 DCs Unable to Boot into Active Directory
http://support.microsoft.com/?id=265089

315131 HOW TO: Use Ntdsutil to Manage Active Directory Files from the 
Command
http://support.microsoft.com/?id=315131